Magnetic probe



Augfl, 195o A. H. LAMB 2,517,325

MAGNETIC PROBE Filed April '7, 1947 Patented Aug. 1, 1950 AUNITED STATES PATENT OFFICE "MAGNETIC PROBE ,Anthony H. Lamb, Hillside, N. J.

JApplication April, 1947,. Serial No.5 v7393983 -3.C laims. (Cl. .12S-.1.4)

'-Thisiinvention-relatesfto; a magneticA probe and more .-particuiarlyto a; novel probe "comprising ya permanent-magnet carried byfgafhousingandl including mea-ns.` for-altering themagnetic strength of the field-of themagnet andi the shape of the pattern.

@.A- magneticrprobe made in accordance with this invention is-a V novel `instrument: adapted to a great-.variety ofwusefulf-purposes. It provides a convenient :fand necessary instrument for .physicians, surgeons, fhospital staffs and rst .aid -workersas it can be employed -for the extraction of iron,-steel, andffother magneticsplintersfrom thefeye or.-.skfin\without:painfondanger of cutting or otherwiseinjuring the:` tissue. .-.Ittis jsanitary, andit. can also'befused-by housewives to remove :metal: chips from xrood, it .being a known I fact .that l.such chips,aregeneratedbyt even the best type. vof, canV openers. Such chips may. be` harmf-ulto. the .delicatestomachand intestinal tissues. The. probe .is` useful in industry to remove magnetic; particles from. theair-.gam of. electrical instruments vand. other ...delicate .mechanisms :the

`operation of .which would vbe impaired' by such '1.a permanentniagnetrand including means for ,adjustingthe effective strength ofthe magnet.

An object of this invention is the provision of `.a .-,magnetic ,probe comprising a housing, 'a

v,permanent mag-net, andadjusting .means associfated with the magnet whereby the 'effective strength ofthe magnet. is al function ofthe eX- ltent to..whic h the` .magnet isexpelled from the lhousing.

` More specifically it is anobjectqof this invention to provide a magnetic probe comprising a housing.v in thel generalv form of Vanpencil body, a

permanent magnet carried i .by ...the j. housing, a frnagnetic material associated with 'the magnet i. and 4means eiectiveto alter theA relativev position of Athe magnet Land I-.the .magnetic .material r.'xvhereby the effectivestrength of themagnet is f altered in accordance with the relative. position oflthe magnet `and themagnetic material.

"These and other objects and advantages will be apparent lfrom the following .description when taken with the,... accompanying V.drawings which illustrate several embodiments of ythe f invention. The `drawings .are fvorpurposes .of illustration and are not to beconstrued ,as dening thescope or limits of the invention, rreference being... had for this purposeto theappended claims.

-In thedrawings wherein like-reterence characters refer to.f like` parts in the several Views:

Figure lis alongitudinalfcrossesectional view illustratinga. complete device .made .in accordance :with thisinvention;

Figure 1A 'is .an isometricview. ofthe internal, operative parts;

. Figure 2. is a fragmentary; cross-sectional. view of the device. illustrated in.Figure 1.and.showing the magnet substantially' fully extended, from the housing;

Figure 3.is similar to vligu1e2 but Wththe tip ofthe. housingr broken .aWayto show thereduced character ,ofthe-magnetic field whenthe magnet `is substantially fully retracted within the housing;

Figure Y 4, is a fragmentary, r.cross-.sectional view illustrating another embodiment of the invention;

.Figure 5.is :a fragmentary viewppartially in .crossfsection .and illustrating. a simplied embodiment of the inventiomand Figure ,6 is also al fragmentary, cross-sectional view. of e still another embodiment. .4

Referring now to. Figure v1, amagnetic, probe made inaccordance withthis inventionpcomprises a tubularhousinghaving arear section I0 andataperedl front section I I. VThe two sectionsof the housing may.be.,detachably.united vasby the venactingthreads` I2 topform .a unitary bodyhaving a smooth exterior surface.A and the housing` sectionsmay be made of any suitable materialsuch. as, forexample, a plastic, as shown. Disposed Within thertaperediront section II is v- ,a tube. I3 made of amagnetic material such as within theusectiovn AII orniyixecl inpositionlby cement. AnY assembly of this type prevents axial motion orthetube I3.

Operating through the bushing I5is a threaded rod Iiisaidv rodwhavinga substantially rectangular cross-,section 4wherein two: opposed surfaces arethreaded and the other two opposed surfaces areuplain. [Surrounding one end of the rodj I6 is ak fork shaped member I'Ithat protrudes from A the housing I 0 in the formof a'. knob I8, as shown. The spacing between the forkedends of the mem- .1 D ber I'I is such that rotation of the knob I8 causes rotation of the rod I6 causing the latter to thread through the bushing I5, as shown in Figure 1A. As the maximum diameter of the rod I6 is somewhat less than the internal diameter of the softiron tube I3, the rod I6 moves into or out of the tube I3 in response to rotation of the knob I8.

Disposed within the soft-iron tube I3 is a permanentimagnet l I3 of. bar form and having a somewhatltape'redf outer end. Although the magnet may be retained within the tube I3 by friction, the magnetic attraction between the magnet and the tube will also prevent the magnet from falling out of the housing. It will now be apparent that rotation of the knob I8 in one direction will cause the rod I6 to expel the magnet 4ISI from the tube I3 and the housing. Rotation of the knob in the reverse direction will cause the rod I6 to move away from the magnet in which case the magnet can be pushed back into the tube I 3 by nger pressure. Alternatively, the rod I6 can be cemented or otherwise aixed to thejen'd of the magnet to automatically retract tlle Vmagnet into the tube |3 The magnetic lines ofA iiux emanating from a bar'v magnet in free' air, flow in a smooth wide path from the North to the South pole. However, the normal direction of the flux can be altered by inserting a magnetic material into the flux path, as the magnetic material has a lower magnetic reluctance than air. As shown in Figure 2, the magnet I9 isl well extended from the soft-iron tube I3 and therelatively large field of magnetic inuence is indicated by the dotted lines. Under this condition the effective distance of the magnetic flux from the outer free end of the magnet is a maximum. Figure 3, on the other hand, shows the magnet I9 substantially fully retracted within the soft-iron tube I3. In this case the lines of magnetic ux pass directly to the soft-iron tube and the effective field of the magnetism from the free end of the magnet is a minimum. y

a .Itisnow apparent that the effective strength ofthe Vpermanent magnet, so f ar as concerns useful purposes, is a direct function of the extent to which the magnet protrudes from the tube I3. As the magnet can be expelled from the tube any desired amount by rotation of the knob I8, my invention provides a magnetic probe in which the 4magnetic strength may be adjusted in a convenient manner tomeet desired conditions of use. This feature is of particular importance to physicians and rst aid workers as, for example, in removing a steel splinter `from the eye. Often the steel splinter imbeds itself in the eye in such manner that its position must be changed before it can be extracted safely without painful rupture of the surrounding tissues. Such a maneuver can best be accomplished by employing a relatively weak magnet, that is, one having sufcient strength to impart a motional effect upon the splinter yet not powerful enough to cause the splinter to jump` to the magnet through the tissues. Once having properly positioned the splinter the magnetic strength of my probe can A.readily be increased for iinal extraction of the steel splinter.

Figure 4 illustrates another embodiment of my invention wherein the permanent magnet remains stationary and the soft-iron-tube is movable to effect a change inthe magnetic strength. v.Fixed within a plastic housing 20 is a T shaped member 2l that is affixed to the magnet 22 by cement or other suitable means. A Soft-iron tube 23 is adapted to slide over the magnet 22 and its position is adjustable by means of the iinger operable knob 24 that extends through an opening 25 in the housing 23, substantially as shown. The knob 24 is axed to the tube 23 by cement, solder or otherwise.

Figure 5 illustrates a simplified embodiment of my invention wherein the housing proper is made of a magnetic material. In `this construction the housing comprises a soft-iron tube 25 having a slit 21 in the end and a slot 28 in the side, the latter terminating short of the housing end. Fastened to the magnet is a finger operable knob 29 that extends through the slot 28. By sliding the knob29 to the right the magnet is extended from the housing and the effective magnetic strength is increased. The soft-iron housing 28 adjusts the effective strength of the magnet as described in detail with reference to Figures 2 and 3.

In certain uses of the magnetic probe it is desirable that the magnet proper be provided'with a sanitary covering to prevent direct contact between the magnet and the medium into which it is inserted. The embodiment illustrated in Figure 6 accomplishes this end. The tapered housing 3U may be vmade of a transparent plastic. A tapered magnet 3l may be either moldeddi'- rectly into the tin' of the housing or'cemented therein by a plastic cement 32 substantially as shown. A threaded rod 33 is adapted to operate through the )fixed bushing 34 in a manner similar to that described with reference to Figure -1f. Cemented to the end of the rod 33 is a soft-iron tube 35 slidableover the magnet 3i. Rotation of the rod 33 will cause the tube 35 tooverlie the magnet to a greater or lesser extent thereby altering the effective field of the magnetic flux emanatingfrom the tapered end of the magnet.

While I have illustrated and described constructions employing a simple permanent magnet and a magnetic flux altering means comprising a soft-iron tube surrounding the magneirthe in"- vention is not to be limited to this particular combination. It will be apparent to those skilled in the art that the flux altering` means may take the form of a simple fiat bar of magnetic material rather than a tube. In fact the flux altering means may itself be a permanent magnet. Therefore. the term ux altering means recited in the claims is intended to cover any coinbination of a permanent magnet and a cooperating magnetic member arranged to alter the path of the magnetic ux emanating from the end of the magnet for the purposes and in the manner specified. Y l

Having now described my invention, its utiilty and mode of operation, variations in thev size, form, arrangement and relation of the parts will be apparent to those skilled in the art. Such variations may be made without departing from the spirit and scope of the invention as set fort in the following claims.

I claim:

1. A magnetic probe comprising a tubular housing, a permanent magnet of bar form having an inner enddisposed within one end of said housing iiux altering means eifective to change the path of the magnetic fiux emanating from the outer end of the magnet, and means operable externally of the housing to alter the relative position of the magnet and the iiux altering means.

2. The invention as recited in claim 1, where in the flux altering means is fixed with respect 5 to the housing and the position of the magnet is adjustable with respect to the ilux altering means.

3. A magnetic probe comprising a tubular housing, a magnetic tube disposed in fixed position at one end of the housing, a permanent magnet slidable within the magnetic tube, a rod movable axially to expel said magnet from said magnetic tube, and `means operable externally of the housing to impart axial motion to the said rod.

ANTHONY H. LAMB.

6 REFERENCES CITED The following references are of record in the file of this patent:

5 UNITED STATES PATENTS Number Name Date 1,410,660 Duclos Mar. 28, 1922 1,597,500 Alexander et al Aug. 24, 1926 2,390,339 Ullman et a1. Dec. 4, 1945 1 FOREIGN PATENTS Number Country Date 441,632 Germany Mar. 8, 1927 

